Avian Influenza Threatens Vultures Worldwide
A highly pathogenic avian influenza virus is causing rapid declines in vulture populations across multiple continents, threatening an essential ecosystem service. At least 16 of the 23 vulture species are now of conservation concern, with confirmed deaths in the Americas and Europe.
Avian influenza is accelerating a global vulture crisis, pushing essential scavengers toward extinction. The highly pathogenic H5N1 virus, causing a panzootic in animal populations, has now been confirmed in species from the bearded vulture in Europe to the California and Andean condors in the Americas. Sixteen of the world's 23 vulture species are now of conservation concern due to this emerging threat.
Vultures are remarkably resistant to many pathogens but are highly vulnerable to H5N1, which has a high fatality rate in both domestic and wild animals. The virus has already killed thousands of American black vultures and turkey vultures across the United States and South America. More than 48 species of mammals have also been infected, underscoring the virus's broad reach.
Rapid population decline in California condor
The virus's immediate impact is starkly illustrated by the critically endangered California condor. Its wild population fell by 6% in just six weeks. This precipitous drop prompted a vaccination campaign for the species in the United States, a rare emergency intervention for a wild bird population.
Feeding stations increase contagion risk
Conservation measures designed to help vultures may now be contributing to their decline. Vultures naturally gather at feeding stations, where they consume provided carcasses. Research confirms this congregation creates ideal conditions for the rapid spread of contagious diseases like avian influenza. Jon Morant, a researcher at the University of the Basque Country, explained the broader risk: "It has been proven that [scavengers] help prevent or reduce the spread of pathogens. That is, they prevent disease-causing microorganisms from continuing to spread." The loss of vultures, therefore, removes a critical barrier against wider disease outbreaks.
Vaccination and monitoring recommended
In a letter published in the journal Conservation Biology, an international team of researchers outlines an urgent response plan. Led by Jon Morant, the team proposes five key courses of action to mitigate the threat.
The situation varies by species and region. For instance, while the griffon vulture population in Spain's Basque Country remains healthy for now, the related Egyptian vulture is known to be more sensitive. The authors stress that a one-size-fits-all approach will not work.
